The present invention relates generally to system and methodology for fuel monitoring, which may be adapted to form a pollution control apparatus and particularly to form an apparatus that prevents undesirable fuel spills from a fuel tank, in particular a marine craft fuel tank.
Boaters have significant problems in fueling their boats due to fuel spills. In boats with integrated tanks, spills typically occur through a safety vent line. However, ejection of fuel into any river, lake, bay, inlet, or harbor is harmful to the environment and potentially immediately dangerous to boaters (from fire, explosion, or contact burns). In addition, such discharges (intentional or accidental) are against federal law and can result in a fine of up to several thousand dollars. When it is considered that there are literally hundreds of thousands, if not millions, of boats in the United States with integrated tanks, many with three or four such tanks each, and that such may be fueled as often as weekly, it can be reasonably estimated that possibly even millions of gallons of fuel are unintentionally and/or unavoidably discharged into the waterways each year.
Approaches for preventing this problem are disclosed in my U.S. Pat. No. 5,229,766 for Marine Fuel Tank Pollution Control Apparatus and are incorporated herein by reference thereto. In general, such approaches include mechanical means for either blocking fuel flow through the vent line or capturing the overflow.
Additionally, devices are known which have the purpose of attempting to detect various overflow conditions, though not all in a marine safety environment. For example, U.S. Pat. No. 5,028,910 to Meacham discloses a drain overflow alarm for a washing machine drain which includes means to disconnect the power supply to the washing machine and to notify the operator. Similarly, U.S. Pat. No. 4,418,712 to Braley discloses an overflow control system for use with home appliances which detects liquid level in a stand pipe and shuts power off whenever such level reaches a predetermined limit. U.S. Pat. No. 3,811,051 to Merrell discloses a capacitance responsive detector system which issues a warning when the liquid level in a tank is too low.
By way of further background generally, other devices are known for variously indicating or detecting fluid level. U.S. Pat. No. 4,967,181 to Iizuka discloses a fuel level gauge provided with an apparatus for issuing a warning on the amount of remaining fuel for use in particular with automobile fuel tanks. U.S. Pat. No. 4,149,412 to Fish discloses a level measuring apparatus that includes a timer responsive to changes in capacitance of a probe due to changes in the level of material in a container.
U.S. Pat. No. 4,102,191 to Harris discloses a digital fuel gauge for monitoring the liquid level in a fuel storage tank. U.S. Pat. No. 3,335,414 to Meserow discloses a critical condition warning device to indicate or signal a low fuel level in the fuel supply of an internal combustion vehicle.
U.S. Pat. No. 2,756,410 to Tobias discloses a liquid level warning device for indicating the volume of liquid contained within a tank located at a point remote from the device. U.S. Pat. No. 1,796,586 to Bradshaw discloses an electric indicating means for indicating the quantity of liquid in a tank. U.S. Pat. No. 1,049,952 to Walton discloses a water level indicating system for indicating the varying levels in the water ballast tanks of the bilge of steamships.
Still further systems are shown by other exemplary U.S. patents, as follows.
______________________________________ U.S. Pat. No. INVENTOR ISSUED TITLE ______________________________________ 3,680,044 TSUBOUCHI 7/72 LIQUID LEVEL INDICATING ARRANGEMENT FOR VEHICLES 3,204,230 HOSFORD, JR. 8/65 FLUID LEVEL INDICATOR 4,963,169 GRANVILLE 10/90 FUEL TANK VENTING SEPARATOR 258,872 ASHCROFT 6/1882 WATER AND STEAM SEPARATOR 3,849,771 APPLIN 11/74 LIQUID LEVEL ALARM 912,970 MARSH 2/09 ELECTRIC ALARM WATER GAGE 973,772 GEDEON 10/10 VESSEL LOADING ALARM 1,348,015 LEE 7/20 LEAK DETECTOR FOR VESSELS 3,185,789 GUNTHER 5/65 FLUID OVERFLOW SWITCH APPARATUS ______________________________________
The complete disclosures of all the above-indicated patents are fully incorporated herein by reference.